Butterfly Aggression

We started seeing our first regal fritillary butterflies of the season last week, and began our second year of data collection on their habitat use in the Platte River Prairies.  As always, male fritillaries have emerged first and now have to wait a couple more weeks before females arrive on the scene.  In the meantime, they do some nectaring, but mostly seem to just fly around.  They look like a bunch of teenage boys who arrived at the school dance before the girls…

A regal fritillary butterfly seen last week in the Platte River Prairies, Nebraska.

The above regal fritillary was nectaring on a plant that will remain a mystery until my next post (sorry).  I was expecting to see them nectaring on common and showy milkweeds (Asclepias syriaca and A. speciosa) because those plants were just starting to bloom.  In some studies of regal fritillaries, milkweeds are major nectar plants.  Last year we saw regal fritillaries using hoary vervain (Verbena stricta) more than anything else, but I didn’t see a lot of milkweed blooming last year – for some reason.  This year, I figured maybe we’d see something different since milkweeds seem to be having a good year.

As I walked around checking milkweed flowers for butterflies, I saw a number of insect species using them, but none more abundant than the gray copper butterfly.  In fact, I saw one flower that had six coppers on it at the same time.

A gray copper butterfly on showy milkweed. The Nature Conservancy's Platte River Prairies, Nebraska.

I did see a few regal fritillaries nectaring on milkweeds, but surprisingly few, given the high numbers of both fritillaries and milkweeds I was seeing.  Eventually, I decided to just sit for a few minutes in front of one milkweed plant to watch the gray copper butterfly that was nectaring on it.  I figured I’d get to see a parade of other insects come by and nectar there as well.

I saw a fritillary making its way toward the flower and got my camera ready so that I could capture both the fritillary and the copper on the same flower.  However, when the fritillary got within a few feet of the flower, the copper suddenly erupted off the flower and flew straight at the fritillary, chasing it like a small bird chases a hawk.  The fritillary swerved off and sped away.  I saw the same thing happen twice more within the next several minutes.

What looks like a peaceful scene with a pretty butterfly nectaring on a flower belies the bottled up aggression waiting to boil over when another butterfly strays too close...

Throughout the day, I saw the same aggressive behavior by coppers on other milkweeds as well.  It’s hard to say, of course, whether the coppers were really protecting their nectar source, but that’s what it looked like to me.  There has been considerable discussion in the scientific literature about whether or not male butterflies (of some species) defend territories like birds do – keeping other males away.  There seems to be consensus that at least a few species do.

What I was seeing, though, was not mating territory defense.  Assuming that coppers can recognize the difference between their own and other butterfly species, they didn’t appear to be chasing away potential competitors for mates.  Instead, they appeared to be monopolizing a valuable food source.  Even when there were multiple milkweed flowers on a plant, or several plants in a clump, coppers successfully chased fritillaries away as they approached.  Interestingly, while coppers wouldn’t tolerate fritillaries, they didnm’t seem to mind sharing flowers with other coppers…  There weren’t many individuals of other butterfly species around, so I didn’t get a good feel for whether coppers chased away all other butterflies or just fritillaries.

I’ve not seen or heard of this kind of behavior before, but I’m sure other people have.  I’d sure appreciate hearing from you if you know anything about it.

Aggressive butterflies… who’d have thought?

46 thoughts on “Butterfly Aggression

  1. Last week and the week before we started seeing fair numbers of Regals down here in Pawnee County. One place we were seeing them concentrated was on the roads (graveled with white rock) within Burchard Lake WMA, which were moist from recent rains. We guessed they were getting minerals from the moistened road surface.

    • It’s interesting isn’t it… I suppose maybe the regals are like hawks being chased by smaller, more agile birds? Hard to fight back, and easier to just find another flower?

      • I live in southern Rock Island County Illinois and they are even chasing our hummingbirds away very aggressively even as far as 20 or 30 yards. I have never seen this behavior ever in a butterfly.

        • I live in NW Ohio and a butterfly is “standing guard” at our hummingbird feeder – chasing away hummingbirds AND wasps!

          • I found this article by searching on “butterflies harassing hummingbirds” after watching 2 butterflies chase hummingbirds away from my feeder for the last 15 minutes. It’s not the feeder the butterflies are defending though; it’s the flowering plant hanging next to it. The feeder is apparently too close. I’ve never seen this behavior before and thought I was imagining it until it happened several more times. The biggest surprise to me was how successful the butterflies were; the hummers seemed to scare quite easily. What’s a butterfly going to do? LICK them to death??? And the butterflies were thorough, chasing the birds a good 12 feet away before giving up and coming back to the flowers. I didn’t even realize butterflies could keep up with hummingbirds; they flew just as fast as the birds and matched their evasive maneuvers!

  2. I wonder how many butterfly species do this? We have a gravel boat launch where, as Stephen Winter observed above, butterflies congregate. I also figured that they must be after the minerals in the moist gravel. It’s a great place to do butterfly watching and looks for all the world like a pasture, but instead of cattle, it’s butterflies. I’ll see giant swallowtails and eastern tiger swallowtails grazing side by side with five or six “summer” spring azures an inch or so away and pearl crescents a little farther away. None of them minds the presence of the others.

    • Good question. First time I’ve seen it, and I’ve seen the kind of mult–species mineral feeding behavior you mention too. I don’t know if it’s certain species or certain situations that lead to aggression – or both? (Or neither, and I’m just delusional!)

  3. Hackberry butterflies are notoriously territorial, chasing after just about anything of any size that flies by. If a person comes by, they fly out and light on him/her to drink sweat, a source of mineral nutrients.

  4. I live in the westside of San Antonio Texas. We have had many Monarchs and Gulf Fritillary lay their eggs on our Milkweed. I was surprised to see the Fritillary attacking the Monarchs on two occasions. The Monarchs had just emerged from the chrysalis and were drying their wings when the fritillary attacked. The Monarch finally managed to get away. Very disturbing since I never imagined that butterflies were aggressive.

  5. I just saw numerous Aprodite fritillaries attacking a lone Monarch that tried to feed on the same or nearby milkweeds. The fritillaries would feed side by side with each other, but if the Monarch came into sight at all they left the milkweed and mobbed the Monarch. Then I saw the friitillaries do the same thing to a Diana (again larger than themselves), but they paid no attention at all to a smaller Silver-spotted skipper. As mentioned in another post, it is almost like small birds mobbng a larger hawk!

  6. Thanks for your post…I’m glad to know I wasn’t imagining things. Yesterday I was watching my butterfly bush and it looked like a monarch and a fritillary were competing for it. one would be feeding and the other would dive bomb, chasing it around the yard. I even saw two monarchs join together to chase the fritillary,

  7. A man I work with asked me why a butterfly was acting in an unusual way- not only sticking around very specific parts of his yard, but was also not afraid of people, allowing him to walk right up to it and look it over. The biggest surprise was his account of it repeatedly chasing off dragonflies! I’m working on ID’ing it; perhaps this is the culprit… I could see defending resources from competition, but harassing predators? Strange.

  8. I live in Miami and I’m new to raising butterflies, but within a few weeks have lots of monarchs and fritillaries. On two occasions this week I’ve observed a fritillary attacking a newly emerged monarch (flying close and even landing on it), making the monarch flap its wings before it was ready to do so. In both cases the wings of the new monarch were damaged. One seemed to recover and the other couldn’t.

  9. OK ever seen a Skipper, specifically the Common Banded Skipper chase away a Humming bird (Female Ruby) ? I have a White Crepe Myrtle next to a Humming Bird feeder. If the Humming bird approaches to feed the skipper will chase it away. Here is an instance of an insect chasing off a bird!

  10. I have developed a garden filled with Milkweed and many nectar flowers in order to try and encourage Monarchs. Yesterday, I spotted a Monarch and was very relieved and happy. Then, four Spangled Fritillaries chased the Monarch away. This happened several times. We have a very large population of Frittillaries and I am wondering if they will prevent the Monarchs from laying eggs?

    • Stephanie, it’s a good question (and a fun observation!) I don’t know if the Fritillaries will prevent the monarchs from laying eggs or not. You’ll have to let me know what you find out!

  11. Brandon Florida: just watched swallow tail chase monarch away. There are SSooooo many flowers to go, certainly enough for all to share. Kindof sad..

  12. I dug up my maypop vines today because the gulf fritillaries are so aggressive with the monarchs I raise. The frits have attacked many monarchs in my yard…not just chase the monarchs away but 2-3 frits at a time cling on and subdue a single monarch. This is just the second year I have noticed such aggressive frit behavior.

  13. Orlando, Fl: Built a butterfly garden earlier this year, mostly pentas and milkweed for butterflies, but also a purple sage and sweet almond plant for the honeybees. We have a lone monarch that will chase other monarchs, dragonflies, and even birds out of our yard, diving on them all! This may be the same monarch we witnessed being attacked by wasps early in the season, which may be the source of its aggression. There are some moths it will not pursue, but I believe that is because they are smaller. The monarch does not seem to be bothered by humans.

  14. Pingback: Has Anyone Else Seen Butterflies Chasing Away Other Butterflies or Birds? | Natural Crooks Ramblings

  15. I’m seeing frits and swallowtails but not a single monarch for weeks.. the milkweed is recovering nicely, but where oh where are the monarchs? Did they go north of Tampa Bay to escape heat?

  16. I was just chased into the house by a Hoary Edge Skipper. In NJ, I was watering the various vegetables and flowers in my gardens. I saw the butterfly and tried to water around it. Well, I guess I must have made it move one too many times because, it came at me and buzzed my head a few times. Then landed on the chain link fence in front of me and watched me. I watched it back. As I turned to turn the water hose off, it took flight again and circled me. It was the strangest thing I’ve seen a butterfly do. Needless to say, I immediately came inside and googled ‘aggressive butterflies’ and i came upon this site. I was looking for information because, I still have the other side of the yard to do. O.O

  17. I live in Sonoma County in California and have passion flowers and wild milkweed in my yard. Last year the Fritillaries fed on the passion flower leaves and the butterflies stayed in the year, getting nectar from some Verbena and milkweed flowers. In the fall, when the Monarch caterpillars hatched into butterflies, I witnessed Fritillaries grouping together to attack a Monarch who was hanging from a branch, drying his/her wings. The Fritillaries looked to be bumping the Monarch and landing nearby and trying to pry the Monarchs feet from the branch. Luckily the Monarch was able to stay long enough to dry his wings. This year I’ve been watchful and seen the Fritillaries patrolling the Milkweed flowers, at least that’s what it looks like, and chasing off any Monarchs they find. Sometimes the Fritillaries seem to enlist the aid of other Fritillaries when there is a Monarch that needs chasing off. The Fritillaries don’t bother with bees or wasps that visit the Milkweed. Crazy!

    I had never heard of this kind of behavior before and have enjoyed reading about other folks observations. I’m surprised that butterflies have the brain capacity for cooperative behavior like this. Very interesting!

  18. Just witnessed some gulf fritillary butterfly chase a dragonfly…monarchs and it’s own species around my lantana and near their own caterpillar food source. I just assumed it was this butterfly that was the only aggressor 😆

  19. Love the comments to your post! Today I saw a group of Eastern Tiger Swallowtail butterflies acting like thugs with mallard ducks at a stream. The ducks were resting on very shallow bank with many small stones. The butterflies landed a foot from them. Suddenly, each butterfly took off, flying around the bank, and dive bombing a resting mallard’s head. This happened repeatedly over 20 minutes, and I caught it briefly on film.

  20. Just read your post on agressive butterflies . I have a little butterfly habitat and my five butterflies emerged three days ago . Just before I walked over to watch them open their wings as I so often do ,but one butterfly I noticed was actually picking on two other butterflies . Kind of like bullying them ,do you know why this ? They have a piece of fresh fruit I put in tge habitat daily but they are not near tge fruit when tge butterfly is showing his aggression . The butterflies are hanging on the side of the habitat when this happens ,thanks for any answers

      • I have a dog who plays with butterflies almost every day in our yard, she is in the middle of the yard and all of a sudden they show up. they flutter down to her and then fly up and land all over and fly away when she sees them and goes over to them. they also land very near me while I watch my dog I’m on my deck. my dog now looks for them if I say where are the butterflies.This has been going on since last year. Are there butterflies attracted to the scent of dogs

  21. I just witnessed a battle between a swallowtail butterfly and a hawk moth! I’ve never seen anything like it before and I spend a lot of time outside. These comments make me think one or the other must have been protecting their food source. The duel lasted 4-5 minutes and the hawk moth almost ended up in the pond. It eventually recovered enough to fly into a bush. The swallowtail also flew into the bush then up into the trees.

  22. I was just looking up butterfly aggression and happily found this! Today, the 4th day of fall, hubby and I were sitting out on our patio, when a little (Epargyreus clarus) Silver-spotted Skipper sat atop our fire pit cover. When a bug or other butterfly would fly past it, it flew up and seemed to chase it away, then set back down on the cover. I was amazed at this behavior! I jokingly told hubby not to agitate it, he had taken his socks off, waved them a bit and said “I’ll f* you up butterfly”. We laughed until he flew off again and came back and fluttered (viciously attacked) at my my husbands eye! Amazing!

  23. Working at a remote site north of Sayre Oklahoma, right now. Watching a pair of dark colored butterflies harass groups of swallows. Couldn’t believe my eyes at first but it’s happening.

  24. Just found this post because I witnessed buckeye butterflies chasing dragonflies in a meadow. San Francisco Bay Area.

  25. I’m glad this post was created so there’s documentation of this type of behavior. I just witnessed a monarch attacking a painted lady. The little one was chased into my tall grass until it escaped from the monarch. Wacky!

  26. Yesterday I say a butterfly (might have been a fritillary) harass a hummingbird at the hummingbird feeder until the hummingbird left and butterfly settled on the feeder – Minnesota

  27. I came to your site because I too am curious about butterflies chasing birds; who would if thunk it? It happens near out bird feeders, butterflies will chase Red-winged Blackbirds, even change their target. I didn’t know yh

  28. I have seen fritillaries (can’t recall which type by name) chasing off hummingbirds with an aggression and speed I did not think possible. I’ve seen it too many times now to deny it is actually happening. And for several years could not, for a time, believe my eyes. I live in New York State. Thanks for this post.

  29. I have been so scared to go out of my house because of them.
    I read an article about something like this, this proves my point to my grand kids and family. I hope that you are safe.


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